Damn, we are one Smooth Criminal. At this rate, Ando's going to be short one harem, or at least several haremettes.
[X] Leave the classroom early, head to the school rooftop, and wait for Shirokami and Ando to show up in order to eavesdrop on their meeting which you have little doubt will be about Phantoms and last night's events. All while hidden from sight.
Okay, we get their view on what happened, maybe see if we learn anything new and see if we can figure out what the key and the secret we're going to steal are.
Also, I wonder if the delinquent with the pomp that Ando fought last night is meant to be a recurring character? He might be the comedic sidekick who gets his ass kicked a lot and never quite reaches the main character's level, but still has a lot of heart and gets some cool wins every now and then. You know, like Kuwabara from Yu Yu Hakusho.